原生Ajax post提交

function CreateXmlRequest(){
	var xmlHttp=null;
	if(window.XMLHttpRequest){
		xmlHttp=new XMLHttpRequest();
	}else if(window.ActiveXObject){
		try {
			xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
		} catch (e) {
			try {
				xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
			} catch (failed) {
				xmlHttp=false;
			}
		}
		
	}
	return xmlHttp;
}

function CreateAdd(){
	var username=document.getElementById("username").value;
	var password=document.getElementById("password").value;
	alert("password="+password)
	var request=CreateXmlRequest();
	if(!request){
		document.getElementById("show").innerHTML="当前浏览器不支持javascript";
	}else{
		var content="username="+username+"&password="+password;
		request.open("post","addObj",false);
		request.setRequestHeader("Content-type","application/x-www-form-urlencoded");
		request.send(content);
		request.onreadystatechange=function(){
			if(request.readyState==4){
				document.getElementById("show").innerHTML="loading...";
				if(request.status==200){
					var result=request.responseText;
					alert(result)
					if(result=="add"){
						document.getElementById("show").innerHTML="增加成功";
					}else if(result=="notadd"){
						document.getElementById("show").innerHTML="增加失败";
					}
				}
				
			}
		}
		
		
		
		document.getElementById("show").innerHTML="";
	}
}